The Novel Sunscreen Compositions presented in the instant invention had their genesis with the Petitioner's entry into this area of expertise and his continuous work in development and improvements in the field of Sunscreen emulsions, emollients and final formulations since April, 1982.
Initially, in 1982 the sunscreen molecule of choice was a derivative of p-amino benzoic acid, octyldimethyl p-amino benzoate.
Petitioner's work with formulations with p-methoxy-2-ethylhexyl cinnamate gave results equal or better than the use of octyl dimethyl p-amino benzoate.
The development continued with the new uses of diethanolamine cetylphospate and more recently, the use of potassium cetyl phosphate in sunscreen formulations to give oil in water emulsions which gave waterproof sunscreen formulations.
The Petitioner's further goal was to discover a water dispersible, self emulsifying surfactant that would be oil soluble and simultaneously have emollient properties with a desirable skin feel. This surfactant when added to H.sub.2 O at room temperature would form its own oil in H.sub.2 O emulsion and at the same time appear and feel like a cosmetic skin lotion. In addition, the surfactant would be stable, safe and effective at use concentrations.
The result of this effort is U.S. Pat. No. 4,559,226 which introduced at least two self-emulsifying alkoxylated esters having the structural formulas: ##STR2##
Increasing the hydrophilic portion of structure b, to cause water solubility, the resulting compound has the following structure: ##STR3##
The resulting compound, that is, CUPL.RTM. PIC became a fragrance solubilizer and oil in water emulsifier.
The aforementioned Hetesters.RTM. and CUPL.RTM. PIC proved to be excellent oil in water emulsifiers, emulsifying at least twice their own weight in oil. They further proved to be excellent pigment wetters and dispersers.
Both the Hetester.RTM. & CUPL.RTM. are synthesized and do not contain any animal derived components. They are free of phenolic and oleic groupings. These properties result in non-distortion of fragrances, less tachiness and excellent safety scores.
Recently, U.S. Pat. No. 5,116,604 was issued. The preferred embodiment of this invention has the following structure: ##STR4##
This unique ester was produced by using a specific C-20 alcohol clearly defined in the Patent. The use of this specific C-20 alcohol resulted in a neopentanoate ester with an extraordinary emolliency that significantly enhances the sun protective factor (SPF) of a sunscreen formulation. In addition, it has these desirable properties: clear, low-freezing liquid, good color, odor, non-comedogenic, stable and safe. It is also a moisturizer and pigment wetter for cosmetic products.
Progressing further, various uses of the Hetester.RTM. and CUPL.RTM. surfactants in combination with the oil soluble ester, Elefac.RTM. I-205, gave a water thin, oil in water emulsion without the need for stabilizing water dispersible thickeners. The emulsion thus formed was stable for 3 months at 50.degree. C. and had a perfect freeze/thaw stability.
The instant presentation is the end result of continuous pursuit of excellence in this field.
P-methoxy 2-ethyl-hexyl cinnamate produced results which were equal or better than the leading UV absorber in 1982, octyl dimethyl p-amino benzoate.
Diethanolamine cetyl phosphate is an unusual surfactant soluble in hot (85.degree. C.) oil and water forming an oil in water emulsion which gives waterproof properties to the sunscreen formulation. Potassium cety phosphate, recently in use, gives similar results in the preferred embodiment.
The alkoxylated ester, Hetester.RTM. PHA, as above gives emulsions at room temperature.
The aforementioned alkoxylated ester CUPL.RTM. PIC is a solubilizer and emulsifier.
The neopentanoate ester, Elefac.RTM. I-205, is an SPF booster and emollient. The SPF boosting power of Elefac.RTM. is similar to the boosting power of water soluble UV-B additives.
Recently, Petitioner filed a Patent application for Novel Oil in Water Emulsions. The application introduced the use of Hetester PHA, CUPL.RTM. and Elefac.RTM. I-205 in combination to give water thin oil in water emulsion without the use of water dispersible gums. Using this emulsion system also resulted in unexpected high SPF readings with the use of p-methoxy-2-ethyl-hexyl cinnamate in the formulation.
Finally, using this emulsion system resulted in a water dispersible sunscreen formulation free of undesirable PABA, PABA derivatives and Benzophenone-3.
The use of this emulsion system and p-methoxy 2-ethyl-hexyl cinnamate and 1-(4-methoxyphenyl)-3-(4 tert-butyl-phenyl) propan-1,3-dione in the formulation also resulted in higher than expected SPF readings.
As a result of the Petitioner's work in this area, the present state of the art now includes sunscreen formulations exhibiting high SPF scores without the use of the undesirable PABA, PABA derivatives and Benzophenone-3 and other absorbers. In addition, some of the sunscreen formulations exhibit waterproof properties without the use of any polymers again with higher than expected SPF scores.
Sunscreen formulations have attained a major prominence as a result of recent studies indicating a relationship between skin cancer and exposure to the sun.
Sunscreen formulations for use on human skin are widely used and are available for diverse consumer needs. Different formulations give different Sun Protection Factors (SPF) values from 2-4 (minimal protection), 4-6 (moderate protection), 8-15 (maximum protection) and above 15 to indicate ultra sun protection.
There are a varied number of problems encountered in sunscreen compositions and the sunscreens used.
PABA and PABA derivatives used cause stains and may be problematic for people allergic to these chemicals. Benzphenone 3 presents solubilization problems in sunscreen formulations affecting stability of the finished formula and may also be sensitizing and cause alergy problems.
The polymers used in vehicles carrying waterproof sunscreens, also may cause non-consistent distribution on the skin and uneven sun protection making them undesirable by the consumer.
The introduction of the emulsifiers, Hetester.RTM. PHA, CUPL.RTM. PIC and Elefac.RTM. I-205 alone or in combination has eliminated all of the aformentioned problems encountered in sunscreen formulations.